In the present day, the purification of polluted water is a topic that has been sufficiently developed. There are currently many systems on the basis of the characteristics of the polluted raw water that is intended to be purified.
In short, the purification of polluted water consists of a series of chain unit processes (physical, chemical and biological) that reproduce in an enclosure the natural self-purification and they are intended to successively separate the pollutants from the polluted water containing them.
The separation technique of particles in suspension is based mainly on the physical phenomenon of decantation, with different variants and configurations. However, the separation of dissolved and colloidal pollutants is more problematic, requiring physical-chemical treatments and others more advanced.
In the case of polluted water of urban origin, different types of treatment plants are designed depending on the flow rate of water to be treated, the characteristics of the polluted water and the area of available land. Thus, we can find from the simpler, such as septic tanks, to the more complex, such as the so-called waste water treatment stations (WWTS).
In the case of polluted water of industrial origin, the different purification systems are highly conditioned primarily by three factors, such as the flow rate to be treated, the nature of water (acidic or basic), the polluting substances that it has and the concentration of said pollutants.